1. Field of the Invention
The present invention relates to an observation apparatus, such as an optical microscope, stereoscopic microscope or video microscope, comprising an electrically driven unit.
2. Description of the Related Art
Observation apparatuses such as optical microscopes, stereoscopic microscopes and video microscopes are widely used in various fields. Usage includes not only medical science and biology, but also the industrial fields spanning from the inspection of IC wafers and magnetic heads to quality control for a metal organization, and finally to the research and development of new materials.
In recent years, observation apparatuses have been increasingly widely used. An example is when a plurality of observers simultaneously observe specimens on the apparatus as well as an enlarged image of the specimen attached to a work document such as a report. An observation apparatus system is becoming a mainstream in which a charge-coupled device (CCD) camera is connected to an observation apparatus so as to display the pickup image on the application software running on a personal computer (PC) and, associated with the aforementioned setup and operation, electrically driven units such as a revolver incorporating an object lens(es) and a Z-stage used for focusing are remotely operated through the application software running on the PC, and thereby the operability is being improved.
In a method for managing the position of the above described electrically driven unit, at least one sensor is equipped in the drive system to manage the position of each electrically driven unit. This is done on the basis of a relative drive amount from a reference position that is defined as the position of one of the equipped sensors. In such a system, however, the current position of the electric-powered drive unit is not known immediately after the power to the observation apparatus is turned on, and therefore the unit needs to be driven once to a reference position so as to recognize the reference position. Consequently, there has been a problem wherein the observer is required to wait a certain period of time between turning the power on and starting to observe a specimen.
It is accordingly conceivable to adopt a method for managing the position of an electric-powered drive unit immediately after turning the power on by means of an absolute encoder or the like. Such a method, however, is faced with problems such as complicating the configuration and increasing the product cost.
For example, Laid-Open Japanese Patent Application Publication No. H11-202212 has disclosed an observation apparatus configured to return an electric-powered drive unit back to a reference position before turning off the power to the present observation apparatus after exiting the application software, thereby making it possible to eliminate the need to carry out an initializing operation at the next startup, or to drastically shorten the initializing operation time.